The present invention relates to a metal gasket with sealing and connecting sections, which is especially useful for a manifold gasket of an internal combustion engine.
In an internal combustion engine, a plurality of exhaust holes communicating with combustion chambers is situated at one side of a cylinder head and is connected to branch portions of a manifold pipe through manifold gaskets. The manifold gasket is installed between one exhaust hole and one branch portion, but since the exhaust holes are arranged at one side of the engine, in order to easily install the manifold gaskets to the required portions, one manifold gasket with a plurality of sealing sections connected by connecting sections is often used. Each sealing section is located between one exhaust hole and one branch portion to securely seal therebetween.
This gasket can be installed easily to the engine. However, since an exhaust gas with high temperature flows through the exhaust holes, the gasket attaching portions of the cylinder head and the exhaust pipe deform by the high temperature exhaust gas. Accordingly, the sealing sections connected by the connecting sections are subjected to lateral forces, i.e. pulled or pushed through the connecting sections whenever the engine is actuated. As a result, the sealing sections connected by bolts may be moved between the gasket attaching portion of the cylinder head and the branch portion of the exhaust pipe to cause mis-alignment therebetween, or the sealing sections may have cracks or damages. Thus, the sealing ability is reduced or damaged.
In view of the above problems, a manifold gasket 10 as shown in FIG. 1, generally disclosed in U.S. Pat. No. 4,728,110, had been made. The manifold gasket 10 includes sealing sections 11 and connecting sections 12 between the sealing sections 11. Each sealing section 11 has an exhaust hole 13, two bolt holes 14 and a bead 15 around the exhaust hole 13, while each connecting section 12 includes a buffer or pressure absorbing portion 16 in a U-shape in section. The absorbing portion 16 expands or contracts according to expansion or contraction of the engine to absorb changes in length between the exhaust holes 13.
The above gasket 10 can properly absorb the change in length between the exhaust holes when the gasket is used. However, when the gasket is prepared, it is difficult to precisely set the length between the exhaust holes because of the buffer. Thus, the exhaust holes and the bolt holes may not be precisely located on the predetermined places or the bead 15 on a plate may be dislocated relative to the other plate. As a result, the exhaust holes in the engine can not be properly sealed by the gasket.
Also, since the buffer has a flexibility, the gasket may be damaged in handling the gasket, or the gasket can not be easily installed on the engine. Further, since the relatively large buffer is formed in the connecting section, when the gasket is formed, an additional step for forming the buffer is required, resulting in increasing the manufacturing cost.
The present invention has been made in view of the above problems in the conventional gasket, and an object of the invention is to provide a metal gasket with sealing and absorbing sections, which can securely seal around the holes to be sealed even if the gasket is subjected to expansion and contraction forces repeatedly.
Another object of the invention is to provide a metal gasket as stated above, wherein the sealing sections of the gasket can be formed easily and precisely while the absorbing section can absorb deformation of the engine.
A further object of the invention is to provide a metal gasket as stated above, which can be installed relatively easily on the engine without deformation.
Further objects and advantages of the invention will be apparent from the following description of the invention.